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Structure of the Current Sheet in the 11 July 2017 Electron Diffusion Region Event
Author(s) -
Nakamura Rumi,
Genestreti Kevin J.,
Nakamura Takuma,
Baumjohann Wolfgang,
Varsani Ali,
Nagai Tsugunobu,
Bessho Naoki,
Burch James L.,
Denton Richard E.,
Eastwood Jonathan P.,
Ergun Robert E.,
Gershman Daniel J.,
Giles Barbara L.,
Hasegawa Hiroshi,
Hesse Michael,
Lindqvist PerArne,
Russell Christopher T.,
Stawarz Julia E.,
Strangeway Robert J.,
Torbert Roy B.
Publication year - 2019
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1029/2018ja026028
Subject(s) - current sheet , electron , physics , magnetic reconnection , field line , electric field , outflow , diffusion , line (geometry) , jet (fluid) , plasma sheet , pressure gradient , substorm , computational physics , magnetic field , current (fluid) , geophysics , atomic physics , magnetosphere , mechanics , geometry , magnetohydrodynamics , meteorology , mathematics , quantum mechanics , thermodynamics
The structure of the current sheet along the Magnetospheric Multiscale (MMS) orbit is examined during the 11 July 2017 Electron Diffusion Region (EDR) event. The location of MMS relative to the X‐line is deduced and used to obtain the spatial changes in the electron parameters. The electron velocity gradient values are used to estimate the reconnection electric field sustained by nongyrotropic pressure. It is shown that the observations are consistent with theoretical expectations for an inner EDR in 2‐D reconnection. That is, the magnetic field gradient scale, where the electric field due to electron nongyrotropic pressure dominates, is comparable to the gyroscale of the thermal electrons at the edge of the inner EDR. Our approximation of the MMS observations using a steady state, quasi‐2‐D, tailward retreating X‐line was valid only for about 1.4 s. This suggests that the inner EDR is localized; that is, electron outflow jet braking takes place within an ion inertia scale from the X‐line. The existence of multiple events or current sheet processes outside the EDR may play an important role in the geometry of reconnection in the near‐Earth magnetotail.